Stalking the Signals
by Tom from New England (a.k.a. Mr. Icom)
Having been an RF hacker for a couple decades, I'm glad to see an increase in interest among technological enthusiasts in the wonders that exploring the radio spectrum has to offer. Things have changed quite a bit since 1987 when I wrote my first article for 2600. What a long, strange trip it's been.
One of the staples of the monitoring enthusiast was RadioShack's Police Call frequency directory. No matter where you lived in the USA, you could walk into the McDonald's of electronics stores and have all the public safety records of your locale and a bunch of useful reference material at your fingertips.
Later issues included a CD containing the whole country's public safety license data, selected businesses, and all the other extras that ensured Tandy Corp. received at least some of your hard-earned cash once a year.
The most useful part of Police Call was something they called the Consolidated Frequency List. It told you what service was allocated to a particular frequency. With it, you could look up a frequency like 45.88 MHz and quickly find out it was allocated to the Fire Service for "intersystem" communications (that frequency by the way, happens to be the inter-county channel for New York State fire departments).
Unfortunately Police Call's last edition was published in 2005. You still might be able to find a copy of the last edition at a local RadioShack and it would be a worthwhile reference just for the Consolidated Frequency List.
The Internet has a number of sources for frequency data. The most popular site is Radio Reference at www.radioreference.com.
Originally a site for information about trunked radio systems, it's probably the biggest site of user-contributed frequency and radio system data on the Net.
The second site is run by the FCC, and is commonly known by the nickname "Gullfoss." It is the FCC General Menu Reports page, which is the whole FCC license database. Its URL is gullfoss2.fcc.gov/reports.
What I like to do is take the latitude/longitude coordinates of the location I'm staying at and do a "Location/ Frequency (Range)" search off Gullfoss for a 5 to 15 mile radius from said location, depending on how populated it is. If you're in a place such as New York City, even doing a one-mile radius search will provide you with more frequency data than you'll initially know what to do with.
The problem with raw license/frequency data is that you could get a dozen frequencies for a specific agency or business and still have no idea what specific use the frequency has.
The Radio Reference site can sometimes help with this, depending on how many active contributing scannists are in the area of interest. Despite the demise of Police Call, there are still numerous "local" frequency directories that may be available at your nearby radio shop.
Those of you in the Northeast who want a nice complete printed directory to hold in your hands are blessed by the presence of Scanner Master in Massachusetts. Their web site is www.scannermaster.com and they sell some rather excellent detailed guides for the Northeast. Their Southern New England Pocket Guide (#01-510885) is a constant monitoring companion of mine along with a well-used Moleskine pocket journal.
Readers of 2600 should be familiar with the Signal Stalker police scanners, since there have been a couple of articles published in previous issues.
Many people have an interest in hearing signals in their immediate vicinity. Upon seeing someone nearby with a handheld radio, they wonder what the frequency is and what's being talking about.
Back in the old days, we used handheld frequency counters like the $99 RadioShack special, or a much more expensive Optoelectronics Scout. There were also "near-field receivers" like the Optoelectronics R-10 Interceptor and Xplorer, but they too were beyond the financial reach of many hobbyists.
The frequency counters worked O.K., but you generally had to get within a hundred feet or so of the transmitter. You also had to contend with continuously transmitting high-power annoyances such as broadcasters and pagers.
The Signal Stalker changed all that.
Instead of carrying around both a frequency counter and a scanner, your scanner serves double duty. Annoying signals can be ignored, and you can immediately hear the signal upon detection. You can scan your usual frequencies and set it to alert you when something nearby keys up.
You no longer have to get as close to a transmitter, as it can detect signals from 1000 feet away. And you could own a Signal Stalker for under $100.
The ubiquitous model was the RadioShack PRO-83 handheld. Now discontinued, it retailed for $120 but was often on sale for under $100. You still might find one at the clearance price of $70. Its lesser-known twin is the Uniden BC92XLT.
Uniden refers to the near-field reception feature as Close Call, but it works the same way as RadioShack. Other than some minor firmware differences, they are the same unit.
A certain infamous retail store chain from Arkansas has it in the mobile electronics department for only $99.99. There are also higher-end Signal Stalker/Close Call scanners available that have extra features such as trunk tracking, P25 reception, and continuous 25-1300 MHz (minus cellular) frequency coverage.
One of the main complaints I hear about the Signal Stalkers is the lack of capability to lock out annoying frequencies while in Signal Stalker mode.
For starters, if you have a Uniden BC92XLT, enable the Close Call "pager skip" function. This will eliminate the vast majority of annoying signals. On both units, when you find an annoying signal in SS/CC mode simply hit FUNC twice and then L/O. This will lock out the frequency. The user manual is a little vague on that.
Unlike frequency counters, the signal acquisition time on Signal Stalkers is a little longer. To shorten this time, deselect bands you're not at the moment interested in hearing activity on.
For example, if you're in the middle of some rural farmland and there is no UHF or 800 MHz activity, then deselect those bands. Since you will probably (note I said probably) not hear anything on the aircraft band unless you live next to an airport, you might want to deselect the aircraft band as well.
You never know what you might be missing however. I don't live near an airport, but I've gotten Signal Stalker hits from planes flying overhead at low altitude.
Many of you who have played with frequency counters were aware of the fact (that a "bigger" (high gain) antenna wasn't necessarily better because of the frequency counter's lack of selectivity. A high-gain antenna attached to a frequency counter usually resulted in the counter displaying the frequency of a local pager or broadcast transmitter.
This is not the case with a Signal Stalker. A high-gain antenna combined with the Signal Stalker's ability to lock out annoying signals and select individual frequency bands will result in an increase in near-field reception range. Using a magnet-mount scanner antenna on the car, I've "detected" my county's fire dispatch frequency from ten miles away, and a five watt VHF-low band R/C link from about 2000 feet.
One thing I noticed about the PRO-83 is that the supplied short antenna is barely adequate. The BC92XLT has a slightly better stock antenna, but as a general rule all stock rubber duck antennas that come with scanners are designed for uniformly average to mediocre performance across a wide frequency range.
I suggest upgrading with a better aftermarket antenna. You can get a RadioShack Cat. #20-034 Deluxe Rubber Duck Antenna for general purpose monitoring, or their Cat. #20-006 Telescoping Antenna for when you're in a fixed location and want optimum reception.
In a similar vein, when driving in a vehicle having the scanner with a rubber duck antenna sitting on the seat next to you won't cut it. Get an external antenna for your vehicle.
While on the subject of antennas, you might be able to scrounge something up depending on what bands you are interested in. CB antennas work very well on the VHF low band (30-50 MHz). Dual-band (two meter and 70 cm) hand antennas will work for the VHF high and UHF bands (138-144 and 440-512 MHz). Old AMPS cellular antennas are perfect for the 800 and 900 MHz bands, but you will need a TNC-to-BNC antenna adapter to use them.
I've received a fair number of emails from people asking what scanner they should buy.
For a basic non-trunk-tracking, non-P25 unit the PRO-83 or BC92XLT is an excellent value for the money just to have near-field reception capability.
When it comes to trunk-tracking scanners, however, I would avoid buying one at the moment. Why? The reason is something called "rebanding." At present the 800 MHz land mobile band is a host to both public safety communications and the Nextel service. This has resulted in interference issues over the years.
To eliminate the problem, the FCC is doing the following:
1.) Moving Nextel to the top of the 800 MHz band and public safety to the bottom. At present, public safety communications are mostly on the edges of the band, with Nextel in the middle.
2.) Changing the channel/frequency spacing from 12.5 kHz to 6.25 kHz. This will double the amount of channels available. Consequently, radio users will have to convert to narrowband modulation.
3.) Eventually moving Nextel off the 800 MHz band and up to the 1.9 GHz PCS band. This is troublesome for trunk-tracking scanners because of Number 2 above. Each 12.5 kHz frequency is assigned a channel number. The channel number/frequency assignments will change when the band goes to the narrower spacing. Trunk-trackers use those channel numbers to determine what frequency to tune in order to follow a talkgroup on the system. After a system has been rebanded, the current crop of trunk-tracking will not follow the system as the channel number/frequency assignments will be all wrong.
New England was supposed to be the first to go through rebanding, and the process has yet to occur as of the time of this writing. I'd expect other parts of the country to go through similar delays.
As far as scanner manufacturers are concerned, RadioShack initially said the firmware of their trunk-tracking scanners would be upgradable but then changed their mind. If you have a current model RadioShack trunk-tracker scanner, you will be out of luck once rebanding occurs to the systems you monitor.
Uniden (Bearcat) has said that their current models will be firmware upgradable and some upgrades have already been made available to correct a few bugs found in early versions of the firmware.
However, I suspect that unless the rebanding progresses quicker, once the "current" models become discontinued, product support (including firmware upgrades) for them will cease to exist as is usually the case with "obsolete" equipment.
Once the FCC, land mobile radio industry, and Nextel get their collective act together and figure out once and for all the final fate of the 800 MHz band, then things will be all fine and dandy.
Until then, if you simply have to buy a trunk-tracker spend as little as possible for a used one at a hamfest. This way you won't feel so bad when it simply becomes a conventional scanner after rebanding.
If you have a large sum of money burning a hole in your pocket, and you simply have to buy something new, get one of those computer-controlled, DC-to-daylight communications receivers made by Icom or AOR.
They actually will never become obsolete. With the computer interface, they can be used with the Trunker software to follow trunked radio systems, even post-rebanding.
They are also readily modified to provide a 10.7 MHz IF output in order to use an AOR ARD25 (Instruction Manual) P25 decoder box for demodulating P25 audio. They also feature full frequency coverage from 100 kHz to 2+ GHz (minus cellular in the United States).
No matter what frequency gets reallocated to what, you'll be able to tune it. As a new RF hobbyist, a communications receiver is more versatile than a police scanner. You can listen to local VHF/UHF public safety communications one week, tune down the spectrum a little bit for shortwave broadcasters and ham radio operators (3880-3885 kHz - AM mode) the next week, do a little experimentation with computerized monitoring the next, and finish the month out playing with monitoring the various digital modes you encounter on the air.
Beyond Police Call 1st Edition, 1994
Police Call 1995 Edition
Police Call 2001
Police Call CD-ROM 5.0 5th Edition